Climate Change in New York Recent Trends and Future Projections Art DeGaetano Professor and Assoc. Chair Dept. of Earth and Atmospheric Science, Director Northeast Regional Climate Center

The Northeast Annual Temperature

New York Winter Trends December, January February Temperature since 1950 1.56!F rise

since 1970 4.8!F rise

Spatial Variation Winter Linear Temperature Trend 19702000

Significant Change in Winter Climate! Boston

42.5

o

4.8 F

42

Latitude o(N)

41.5 41

New York o

40.5

4.8

Philadelphia

40

4.8

39.5

Washington, DC

39 38.5

30

31

32 33 34 35 o Winter (DJF) Mean Temperature ( F)

36

Timing of Seasons By 2070-2099: • Spring will be arriving earlier by 1-2 weeks (lower) or almost 3 weeks (higher) • The growing season is projected to be !Lilacs: 4 days earlier extended by 4 weeks (lower) and up to 6 !Apples: 9 days earlier !Grapes: 6 days earlier weeks (higher) • Summer is expected to arrive earlier by 11.5 weeks (lower) or 3 weeks (higher) and stay longer by 2 weeks (lower) or 3 weeks (higher)

Summer Heat Index

Average Annual Precipitation in the Northeast

New York Extreme Precipitation Events (>2 inches in 48 hrs)

Extreme Event Frequency

Spatial Variation of Days with Snow on Ground 1970-2000

Lake Effect

Sea Level

Lake Levels Erie

Ontario

Lake Levels Michigan-Huron

Superior

The Climate of New York is Already Changing • Annual temperatures across New York have warmed almost 2º F since 1970 • Winter temperatures have warmed by nearly 5! F since 1970 • More extremes in rainfall • Most places are less snowy except LES • The growing season as enlongated

Looking to the Future "What will happen to concentrations of climate altering gases such as carbon dioxide? "What will happen to regional temperature and precipitation?

STEP ONE: Future Emissions from Human Activities A1fi (higher) continued dependence on fossil fuels with material-intensive economy, ~970ppm by 2100

B1 (lower) shift to alternative energy sources with service & informationfocused economy ~550ppm at 2100

STEP TWO: Global Climate Modeling “Backcast” to compare historical simulations with observed climate. “Forecast” to develop future projections of changes in temperature, precipitation, extreme events, etc.

3 different climate models

STEP 3: Global Temperature Change Likely range: 1.1oC to 6.4oC

2oF to 11.5oF

STEP 4: High-resolution regional climate projections

Temp from global climate model

Temperature from downscaling

Projecting Future Climate Change for the Northeast: Rising Annual Temperatures

observations higher emissions lower emissions

Higher: 6.5-12.5oF Lower: 3.5-6.5oF

Since 1970 2oF

Heatwaves and Temperature Extremes: New York City

Photo credit: Associated Press

The Changing Face of Winter

Intraresearch, d.b.a. MapMart

Annual Precipitation

Seasonal Projections Temperature

Precipitation

Extreme Precipitation " "

Heavy rainfall events are becoming more frequent across the Northeast Under both emissions HIGHER scenarios # rainfall expected to become more intense # periods of heavy rainfall LOWER are expected to become more frequent.

Drought

SHORT

MEDIUM

LONG

Lake Temperatures

Vertical Lake Michigan Profile

Brandt, S.B, Mason. D.M., McCormick, M.J., Lofgren, B. and T.S. Hunter, 2002, Climate Change: Implications for Fish Growth Performance in the Great Lakes. American Fisheries Society Symposium 32:61-76

Lake level projections

VanDorn, J., T. Croley, K. Hayhoe, and D. Wuebbles, 2008: Projected 21st century transient changes in Great Lake levels under higher and lower emission scenarios. Journal of Great Lakes Research, submitted.

Key Climate and Impacts Findings • Changes consistent with global warming are already evident across New York • Over next few decades, changes similar under both emissions scenarios • By mid-century, most changes are greater under the higher scenario • By late-century, under the higher scenario many changes almost twice those seen with lower emissions

Field, C.B., L.D. Mortsch, M. Brklacich, D.L. Forbes, P. Kovacs, J.A. Patz, S.W. Running, and M.J. Scott, 2007: North America. In: Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Parry, M.L., O.F. Canziani, J.P. Palutikof, P.J. van der Linden, and C.E. Hanson (eds.)]. Cambridge University Press, Cambridge, UK, and New York, pp. 617-652.

Questions?